Method for preparing glass-fiber reinforced cement composites

Abstract

A modified reinforced non-porous cement composition and composite and the process of preparing same whereby the composites are reinforced using synthetic mineral fibers, such as glass and E-glass fibers. The cement includes a resin dispersion of a polymer, containing acid groups, with a mean particle size ranging from 0.05 and 5.0 microns and the resin dispersion protects the reinforcing fibers from alkaline attack. The water to cement ratio ranges from 0.2 to 0.5 and the weight ratio of the resin to the cement ranges from 0.02 to 0.4. Preferably, the resin dispersion is a thermoplastic resin prepared from monomers containing vinyl groups and the acid groups are preferably carboxyl groups.

What I claim is: 
     
       1. Process for manufacturing a non-porous cement composite comprising the steps of, (a) admixing a water hardening cement, glass fibers, a resin dispersion, and water, to form a cement mortar;   (b) forming said mortar into a predetermined shape; and   (c) hardening said mortar, wherein (i) said resin dispersion comprises a copolymer of about 10% to about 20% by weight of methacrylic acid, about 50% by weight styrene and the balance by weight of butyl acrylate dispersed in water, which resin has a mean particle size of between about 0.05 and about 5 microns;   (ii) the ratio of said water to said water hardening cement ranges from about 0.2 to about 0.5;   (iii) the weight ratio of said resin dispersion to said water hardening cement ranges from about 0.02 to about 0.4; and   (iv) said glass fibers being present in an amount not exceeding about 40 percent by volume.     
     
     
       2. A process as in claim 1, wherein the glass fibers are present in an amount ranging from about 5% to about 10% by volume. 
     
     
       3. A process as in claim 1, wherein the glass fibers consist essentially of E-glass fibers. 
     
     
       4. A fiber reinforced concrete mixture of a non-porous nature comprised of a water-hardening cement mortar having a water/cement ratio ranging from about 0.2 to about 0.5, and a fiber reinforcing composition admixed directly with said cement mortar, said composition comprising glass fibers in an amount not exceeding about 40% by volume and a resin dispersion comprising a copolymer of about 10% to about 20% by weight of methacrylic acid, about 50% by weight styrene and the balance by weight of butyl acrylate dispersed in water, which resin has a mean particle size ranging between about 0.05 to about 5 microns, the weight ratio of the resin dispersion to the cement ranging from about 0.02 to about 0.4. 
     
     
       5. A concrete mixture as in claim 4, wherein the glass fibers are preferably present in an amount ranging from about 5% to about 10% by volume. 
     
     
       6. A concrete mixture as in claim 4, wherein the glass fibers consist essentially of E-glass fibers. 
     
     
       7. Process according to claim 1, characterized in that the water/cement ratio is between 0.2 and 0.4. 
     
     
       8. Process according to claim 1, characterized in that at least part of the hardening takes place at a temperature of between 35° and 100° C. 
     
     
       9. Process according to claim 1, characterized in that the mean particle size of the dispersed particles is between 0.05 and 1.5 microns. 
     
     
       10. Process according to claim 9, characterized in that the mean particle size is between 0.1 and 0.75 micron. 
     
     
       11. Process according to claim 1, characterized in that the quantity of mineral fibers is between 1 and 20% by weight.